PROCEDES DE DEPOLLUTION PAR EXTRACTIONS SUR MEMBRANES LIQUIDES SUPPORTEES ET LIQUIDE-LIQUIDE DU CHROME(III) EN MILIEU CHLORURE AVEC L’ACIDE DI-2- ETHYLHEXYLPHOSPHORIQUE ET L’OXYDE DE TRIOCTYLPHOSPHINE – BASE SUR LEUR MELANGE SYNERGIQUE
DIDI MOHAMED-AMINE 1*, SEKKAL A. R. 1, VILLEMIN DIDIER 2 (1)LABORATOIRE DE CATALYSE, DÉPARTEMENT DE CHIMIE, UNIVERSITÉ DE TLEMCEN, B.P. 119, ALGÉRIE *E-MAIL: MADIDI13@YAHOO.FR (2)UNIVERSITÉ DE CAEN, ISMRA, LCMT, UMR CNRS 6507, F-14050, CAEN, FRANCE, E-MAIL: DIDIER.VILLEMIN@ENSICAEN.FR
The objective of the study is the extraction of chromium (III) using the liquid-liquid extraction (LLE) technique and the supported liquid membrane (SLM) technique using di(2-ethylhexyl)phosphoric acid (D2EHPA), trioctylphosphine oxide (TOPO) and their mixtures, D2EHPA/TOPO, in the absence respectively presence of KCl, in order to compare and optimize these techniques. Prior, a comparative study for chromium (III) extraction using batch/continuous SLM has been conducted. The extraction of chromium (III) in acidic environment (HCl 2M) with D2EHPA (0.17 M), TOPO (0.11 M) and their mixture D2EHPA/TOPO (15%: 10%) dissolved in dichloromethane is explain by the formation of various complexes. The kinetic studies showed that the time to reach equilibrium varies from system to system. The time corresponding to maximum permeability is different from the time corresponding to equilibrium achievement, whatever the system is. In the absence of salts, the batch system gives a better yield than the continuous one, and the yield depends on the used extracting agent. Starting from a 10.24 g/L Cr(III) at pH = 5, a 100% extraction yield has been obtained by SLM extraction in presence of KCl. The combination of D2EHPA with TOPO produced a synergetic effect, both in LLE and SLM techniques and both in presence or absence of KCl. Always the equilibrium is reached in a longer time than using only D2EHPA alone as extracting agent. The number of cycles necessary for total purification of an aqueous solution contaminated with 10.24 g/L Cr (III) is four. The life span of the SLM impregnated with extracting agent is 108 hours. The good stability of the membrane recommends it in industrial applications for chromium (III) removal.
